Nodes or nodelets?

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I am new to ROS and am doing a basic introductory project. The plan is to have 5 robots, all running the same code. This is for a simulation only - the robots are meant to move around the world and perform basic interactions. Two options being considered are:

1. Having the robots consist of nodes running in separate processes for each robot
2. Using nodelets to have the robots run in the same process.

What are the advantages of each option? Is there a real reason to use nodelets instead of nodes in this situation?